The present invention relates to aircraft with electrical fly-by-wire controls and, more particularly, to the architecture of the flight control system for such aircraft.
It is known that an aircraft with electrical fly-by-wire controls has controls, such as sticks, ministicks, rudder bars, etc., equipped with electrical transducers so that they generate electrical control instructions which represent the action that a pilot exerts on them. It also comprises a computer of flight control commands which, on the basis of said electrical control instructions generated by said controls and of control parameters originating, for example, from sensors, produces electrical operating commands that said flight control computer applies to actuators tasked with moving the control surfaces of the aircraft.
It is also commonplace for such an aircraft to have an automatic pilot capable, under certain circumstances, of piloting said aircraft in place of the pilot. As is also known, an automatic pilot consists essentially of a navigation computer and of a control computer. The navigation computer receives guidance instructions (indicated to it by the pilot) and guidance parameters (sent to it by sensors or by an inertial unit, for example), and from these guidance instructions and parameters produces automatic pilot instructions. For its part, the control computer converts these automatic pilot instructions into commands for operating the automatic pilot, which it applies to said actuators of the control surfaces of the aircraft.
Depending on the known embodiments of automatic pilots, said commands for operating the automatic pilot are applied to said actuators either directly or via said flight control computer. In the latter case, it will be noted that said flight control computer receives, from the automatic pilot, said commands for operating the automatic pilot which have already been fully produced and that in consequence its role amounts simply to transmitting said automatic pilot control commands unmodified.
Whichever of these two embodiments is on board the aircraft, it must also, however, be pointed out that, in such a known architecture, it is necessary to provide two control functions, namely one for the flight control computer and the other for the automatic pilot. Aside from the fact that this gives rise to significant costs, it may happen, owing to constraints of the system, that said control functions differ, particularly as regards the calculation power, the acquisition of parameters, the monitoring, etc. It is therefore compulsory to develop and to validate two control functions. In addition, a structure such as this does not make it possible to minimize the delays between the inertial information and the operating commands given by the automatic pilot to the control surfaces.
An object of the present invention is to overcome these drawbacks.
To this end, according to the invention, the aircraft with electrical fly-by-wire controls, equipped with control surfaces capable of being moved by electrically operated actuators, said aircraft comprising:
controls and a flight control computer, said controls being actuated by a pilot and generating electrical control instructions which are sent to said flight control computer, the latter computer generating, from said electrical control instructions and from control parameters, operating commands sent to said actuators to move said control surfaces; and
an automatic pilot capable of piloting said aircraft in place of said pilot and exerting a navigation function making it possible to produce automatic pilot instructions from the guidance instructions and guidance parameters sent to it, and a control function which consists in producing, from said automatic pilot instructions, automatic pilot operating commands sent to said actuators to move said control surfaces,
is noteworthy:
in that said automatic pilot consists exclusively of calculation means producing said automatic pilot instructions from said guidance instructions and said guidance parameters;
in that said calculation means are connected directly to said flight control computer so as to send said automatic pilot instructions to the latter; and
in that said flight control computer, from said automatic pilot instructions, produces said automatic pilot operating commands and sends these commands to said actuators to cause them to move said control surfaces accordingly.
Thus, according to the present invention, the control computer of said automatic pilot is eliminated and it is the flight control computer which fulfils the control function of the automatic pilot. The invention therefore makes it possible to develop and validate just one control function, the latter being embedded in said flight control computer. In addition it makes it possible to minimize the delay between the inertial information and the commands issued to the control surfaces by the automatic pilot. Furthermore, it also offers the possibility of making the responses of the aircraft under manual piloting consistent with those with the automatic pilot in operation.
As a preference, in order to simplify the structure of said flight control computer as far as possible, said electrical control instructions from said controls and said automatic pilot instructions from said calculation means of the automatic pilot are, by pairs, of the same nature. For example:
said calculation means of the automatic pilot produce, from said guidance instructions and said guidance parameters, three automatic pilot instructions which correspond respectively to a commanded vertical load factor, to a commanded roll rate and to a commanded yaw; and
said controls generate three electrical control instructions which are respectively consistent with a commanded vertical load factor, with a commanded roll rate and with a commanded yaw.